Lactate Threshold Training

The term ‘lactate threshold’ refers to an exercise intensity that causes a spike in blood lactate (a by-product of cellular metabolism of glucose) and represents the point at which the muscle cannot clear lactate at the rate it is produced. This causes lactate (and associated acidic by-products) to accumulate in muscle and begin spilling into the bloodstream. This accumulation point is correlated with a decrease in muscle performance output. Lactate threshold training refers to exercise completed at (or just before) the specific exercise intensity range where lactate begins to accumulate.

In order to understand the function of lactate threshold training in CV fitness, it is important to have a clear understanding of lactate, how it is produced and cleared in muscle and its associated effects on muscular performance.

Lactate is a by-product of carbohydrate metabolism. Glucose is used for energy during both aerobic and anaerobic activities. The breakdown of glucose into energy is known as “glycolysis”. This is where the 6 carbon molecules within a glucose molecule are split in two into two molecules called “pyruvate” (which hold 3 carbon molecules each).

When glucose is broken down in the presence of oxygen (aerobic exercise) the process is very efficient at converting glucose to energy with very little accumulated waste. At aerobic intensities, glucose is broken down into pyruvate which then undergoes further metabolic processes to produce ATP. This process is only possible in the presence of oxygen.

Lactate is formed when pyruvate combines with another by-product of the metabolism process (Hydrogen ions). Hydrogen is an acidic molecule (in free form). It is produced in the muscle as part of the process of using ATP for energy. When Hydrogen binds with pyruvate it produces lactate. Lactate is produced whenever glucose is metabolised including during low-level exercise intensities (and even at rest). However, this lactate is cleared inside the muscle because when oxygen is available, the body converts the hydrogen ions attached to lactate to H2O and the remaining pyruvate is recycled as an energy source.

As we start to increase exercise intensity, we make it harder for the CV system to deliver oxygen (at the rate it is required) and remove exercise by-products. An increase in exercise intensity also leads to greater reliance on glucose as a fuel source. An increase in glucose metabolism leads to greater production of acidic hydrogen ions (and therefore lactate) within muscle. When the intensity of exercise we are working at reaches a point where we can no longer keep up with the oxygen demand of muscles (i.e. anaerobic exercise) we can no longer buffer hydrogen ions and recycle lactate into energy effectively. The combination of increased lactate production and an inability to remove it from tissues at the rate it is produced leads to an increase in lactate (lactic acid) accumulation.

During moderate-high exercise intensities, lactate begins to leak out of the muscle. At this point, lactate begins to rise within the bloodstream (detected through lactate testing). Blood lactate levels will continue to creep up with exercise intensity. The exercise intensity that leads to a sharp increase in blood lactate is known as the “lactate threshold” and is indicative of high levels of lactate accumulation in muscle.

What do high levels of lactate in the blood indicate?

When a muscle produces more lactate than it can clear, we start to see deficits in muscular performance. Early research suggested that because lactate levels in muscle were high immediately following exhaustive exercise, this must mean the muscle burn we feel during exercise is due to an accumulation of lactate (or lactic acid). In actual fact, this is incorrect. This theory was debunked in the 80s. Lactic acid is not the reason behind the muscle burn that eventually leads to fatigue and cessation of exercise. The literature now supports two theories for muscle burn we experience during intense exercise. These are microdamage and an increase in muscle acidity.

Micro-damage

Intense exercise causes micro-tearing of muscle and an inflammatory response accompanied by signalling to the brain (pain).

An increase in muscle acidity

This relates back to the accumulation of free hydrogen ions within the muscle (as it can no longer be buffered effectively). Accumulated hydrogen ions lower the pH of muscles making them more acidic (and potentially increasing micro-damage). Blood lactate testing simply tells us that this acidic accumulation is occurring as the presence of lactate spilling into the bloodstream, suggests the accumulation of hydrogen ions has occurred.

The following is a great video that explains the speaks to the process of lactate testing, how to understand lactate threshold and how it relates to training. The end of the video discusses what happens to lactate once it starts pouring into the bloodstream.

Lactate threshold is highly individualised and is obviously closely related to a person’s VO2 Max. This is because the more efficient you are at delivering oxygen to working muscles, the more efficient you will be at clearing lactate within the muscle (as this process depends on the supply of oxygen). Lactate Threshold Training: The Definitive Guide (n.d.) suggests increasing your lactate threshold means you are able to exercise at a higher percentage of VO2 Max (remember those elite marathon runners that can maintain an intensity of 80-90% of heart rate maximum for a couple of hours?).

In general populations, lactate threshold generally occurs during moderate to hard exercise intensities (whatever that is for an individual). The graph below from Lactate Threshold Training: The Definitive Guide (n.d.) shows that blood lactate levels remain very low during low-intensity exercise (<50% of maximum effort). If the intensity continues to increase to moderate levels, you will see that blood lactate begins to rise in a gradual fashion. The first noticeable rise in blood lactate is known as the “aerobic threshold’. This is a tolerable level of lactate production and will not affect muscle performance. As exercise intensity continues to increase toward moderate-high intensity, there will be a linear rise in blood lactate levels. At some point in this moderate-high intensity training zone (depending on fitness level), there will be a noticeable spike in blood lactate. The intensity of work that initiates this spike is known as the lactate threshold.

Obviously, the fitter you are, the faster the pace you will be able to maintain without reaching your lactate threshold. The objective of lactate threshold training is to move the curve to the right. This means you will be able to work at higher intensities without accumulating lactate. It appears the best way to lift the lactate threshold is by mainly working at intensities just below the lactate threshold point, then adding some sessions that take you above this threshold for short periods of time.

Lactate threshold is a key predictor of endurance exercise performance (i.e. running, cycling, swimming, rowing, triathlon etc). The ability to clear lactate production more efficiently is also a key requirement for high-level performance in repeated-effort sports.

The great news is that lactate threshold is highly trainable. In untrained athletes the lactate threshold occurs somewhere between 50-60% of VO2 max (around 55-65% of maximum heart rate). In well-trained athletes, this increases to between 75-85% of VO2 Max (80-90% of maximum heart rate), and in the very elite at or above 90% VO2 max (90-95% of maximum heart rate). This shows that with the right training, a considerable shift in the lactate threshold is possible Lactate Threshold Training: The Definitive Guide (n.d.). The graph below shows the effect of a short period of lactate threshold training:

Physiological benefits of lactate threshold training

While many of these benefits have already been derived from LSD training, it appears lactate threshold training has an additive effect on these benefits. When combined, these benefits allow an athlete to maintain higher exercise intensities without succumbing to the effects of fatigue. Lactate threshold training is designed to help an athlete both increase their tolerance to lactate accumulation and train their body to be more efficient at dealing with exercise metabolism by-products. The key physiological benefits that lactate threshold training elicits are:

• Increased aerobic capacity – being able to use a higher percentage of your VO2 Max during activity
• Increased concentration and activity of mitochondrial enzymes for improved rate of breakdown of fuels into ATP. Leads to greater efficiency of aerobic metabolism, allowing athletes to remain aerobic at higher intensities.
• Strengthens and leads to hypertrophy of type I muscle fibres
• Improves efficiency of both type I and II muscle fibres through increases in mitochondria, myoglobin and capillary density.
• Increased muscle fibre (motor unit) recruitment (than LSD training). This leads to the conversion of type IIb to IIa muscle fibres in endurance athletes.
• Increases stroke volume and cardiac output improving blood flow to working muscles
• Increases muscle glycogen storage 
• Increases blood plasma volume

(Lactate Threshold Training: The Definitive Guide, n.d.)

Lactate threshold training is also thought to lead to the following performance benefits:

• Lifting of lactate threshold to nearer your VO2 max, meaning you can operate at a higher percentage of your maximum effort (Sjodin et al, 1982).
• Enhances exercise efficiency at lactate threshold intensity (Hopker et al, 2009)
• Increases the velocity (and power) produced at lactate threshold (and just under lactate threshold) (Enoksen et al, 2011)
• Extends time to exhaustion at lactate threshold steady state (Billat et al, 2004).
• Improves endurance performance (Priest and Hagan, 1987)

Lactate threshold training also sits in the middle of LSD training and Interval training in terms of volume and offers less risk of overtraining (than LSD) and places less stress on the body than high-intensity interval training. It also appears to have an additive effect to LSD training on movement economy and improves mental toughness for endurance work as you are training at a pace that is a little outside of your comfort zone (Kunz, 2023).

Types of lactate threshold training

Lactate threshold training can be performed in a number of different ways. The most common approaches include:

• Fartlek Training or over-under threshold training: Where the session alternates between intensities over and under lactate threshold.
• Tempo Training: Steady state exercise just below lactate threshold
• Lactate threshold intervals: Also known as longer aerobic Intervals (usually 8-20 mins in duration mainly performed around lactate threshold).
• Supra-threshold intervals: Also known as shorter aerobic intervals (usually 3-8 mins in duration and performed at intensities above lactate threshold0
• Advanced Threshold training: This uses a combination of the above approaches within the same session (reserved for the more elite athlete).

For the purposes of this topic, we will focus on Tempo and Fartlek training approaches for increasing lactate threshold. Interval approaches for lifting lactate threshold will be covered in topic 4 – Interval Training. Let’s look at Tempo and Fartlek training methods in a little more detail. Please note that while the majority of information to come is based on research performed on runners and cyclists, these principles can be applied to all forms of cardio training.

Tempo training is a moderate-hard intensity run performed at a steady pace just below lactate threshold pace. It is a form designed to increase lactate threshold. Tempo training appears to be most used by endurance athletes involved in longer distances (over 10km), however, it can still be a useful training addition to a general aerobic training programme.

A tempo session is described as being a “comfortably hard” session (Kunz, 2023), or around 6 out of 10 in terms of RPE for those new to this form of training (Logue, 2023).

The purpose of tempo training is to stress the body’s maximum ability to clear lactate during a prolonged workout without causing total fatigue (Kelly, 1989). Typically, tempo efforts are performed at a pace that an athlete could maintain for approximately 60 minutes but are only performed for between 20 and 40 minutes (although marathon runners will perform tempo runs of up to 20km which will take longer than this).

This intensity of exercise is ideally just below the lactate threshold. This allows the system to produce the maximum amount of lactate possible during the run (without crossing the threshold for accumulation) and is thought to both increase the tolerance of the muscle to lactate and improve its efficiency in clearing lactate.

Determining your tempo training pace

This is tricky! There are so many theories for determining the correct pace to maintain in a tempo session. Unfortunately, the only truly accurate way to determine where an athlete’s lactate threshold is through monitoring of blood lactate while exercising.

The reason it is so difficult to provide a blanket statement approach for how to choose your tempo pace is because a person’s lactate threshold is dependent on their level of fitness (condition). For well-trained individuals lactate threshold may occur at between 75-90% of their heart rate maximum, whereas for untrained populations this could be as low as 55-60% of heart rate maximum (Logue, 2023).

While we don’t all have access to blood lactate testing devices, here are a few suggestions for choosing the training pace for clients at different levels of condition.

For those who run often (and monitor their running times) the ideal pace for a tempo run appears to be the maximum pace they can maintain for an hour. How to determine your tempo running pace (n.d.) suggests the most scientific method to find out your ideal tempo pace (without blood lactate testing) is to monitor your training heart rate during a 30-minute run. The first 10 minutes of running will see your heart rate climb and then level off at your lactate threshold (your tempo). After the run look at your average heart rate over the last 20 minutes of the run. This will give you your starting tempo pace.

Logue (2023) offers other suggestions for selecting a tempo pace. One for those who are not accustomed to covering longer distances, and one for well-trained athletes:

• For those unaccustomed to running long distances: Run at 15-20 seconds per km slower than your best 5km pace. For example, if you run 5km in 20 minutes (4min/km pace), then your tempo run should be done at a 4-minute 20-second pace.
• For well-trained cardio athletes who track their heart rates: Run at 80-85% of your maximum heart rate figure (i.e. 80-85% of 220-age)

In simple terms, a tempo session should feel like it is performed just outside of your comfort zone but is able to be maintained for the duration of the session (20-40 minutes). You wouldn’t be able to hold a conversation working at this pace, but your breathing should be steady (not ragged). If you finish the session breathing heavily with your hands on your knees, you have likely set a pace that is too fast.

In fact, your breathing may be the simplest guide of all to determining your tempo training pace. When you cross the lactate threshold, your breathing will become a little ragged as your body attempts to off-load the additional CO2 it is producing (due to switching to anaerobic energy system use). The trick may be to find the pace that makes your breathing start to become “huffy puffy”, then reduce your pace to sit just below this.

The graph below illustrates how the “ventilatory threshold” or point where your breathing becomes noticeably more puffing, occurs at around the same point as the anaerobic (lactate) threshold.

Applying the FITT principles to tempo training

As you have seen, the process of applying the FITT principles to tempo training is typically dependent on the aerobic fitness level of the client. Some clients with a long history of cardiovascular training, or who have completed a significant block of LSD training will likely be able to move straight into tempo runs of between 20-40 minutes duration, while others unaccustomed to running for longer durations may need to build up to these durations in a more progressive fashion. The most important factor in gaining the lactate threshold-raising benefits of this training is of course ensuring the intensity of training is correct.

Type	The type of cardio you use to complete tempo sessions relates back to the client's training goals. This form of training is most used by endurance athletes, so tempo training will likely be performed in the mode of training they compete in (i.e. running, cycling, rowing etc). With clients who have more general cardio training (fitness) goals or for those who have injury or joint issues to work around, the choice of cardio for these sessions will either be: The mode they prefer. The mode they hate least. The mode that reduces the impact on the injury or joint issue. Considerations around the competitive environment for athletes (e.g. track, field, road etc) should also be made.
Frequency	Because tempo runs are completed at somewhat challenging intensities, it is suggested that only one to two tempo sessions are completed a week (Lindburg, 2020), especially when other training modes are being targeted concurrently. It is common for endurance athletes to continue to use tempo trainings throughout their training calendars, whereas sporting athletes are likely to employ these training sessions in the general preparation phase (following or in some cases replacing an LSD block and preceding interval training).
Intensity	This has already been covered in detail in the section above. Appropriate intensity for tempo runs is dependent on the training state of the client and can range between 55-60% of maximum heart rate for unfit individuals, through to 75-90% of maximum heart rate for well-trained individuals).
Time (Duration)	Most literature recommends a continuous steady state effort of between 20-40 minutes for best results, however long-distance athletes will often perform longer efforts than this (e.g. marathoners will often run 20km tempo runs in preparation for races). For those just starting out with tempo training, the key is for them to become accustomed to working at just below lactate threshold. This might be best introduced in shorter tempo intervals, for example starting with 2 x 10-minute tempo runs with a 2-3-minute active recovery between them. These can then be extended to 15- minute intervals after a couple of weeks with the aim of completing one continuous 20-25-minute tempo session by the 4-week mark.

Applying progressive overload to tempo training

Progressive overload application can be applied in a number of ways depending on the client’s training goals. Obviously, if the goal is to compete in a long-distance event, then the initial overload principle applied will be to increase the time and/or distance over which the tempo intensity can be maintained (e.g. from 20 minutes towards 40 minutes). This should be done while applying the 10% volume rule, in that no more than 10% total running distance/duration should be added from one training week to the next. This would translate to increasing the length of the run by 1-2 minutes each week (Lindburg, 2020).

For sporting athletes or shorter-duration training goals, the overload principle will likely be applied by manipulating the intensity of the workout. The initial focus will be on maintaining the tempo pace but will then give way to other lactate threshold training modes like Fartlek training, lactate threshold intervals and supra-maximal lactate threshold intervals where the intensity is manipulated, while either maintaining or reducing the duration of the effort.

A key consideration for progressive overload of the tempo training approach is that as the programme progresses, the lactate threshold (and therefore tempo pace) of a client will change. This means the monitoring of heart rate is essential to ensure progressive overload is achieved. If tempo pace is never changed (in terms of movement speeds) then the heart rate at which the speed is produced will begin to drop and the training effect will be reduced.

Common approaches to tempo training

The standard approach	20-40 minute continuous effort at just below lactate threshold pace (however you want to determine this).
The split approach	Involves splitting the tempo runs into two or three segments with short active rest period between sets (2-3 mins). This is not designed to be run at faster pace (still complete at tempo pace). Useful as a means of building up to longer tempo sessions.
Combined approach	This involves mixing a tempo effort with another form of cardio training. For example, completing a 10-minute tempo run, then completing a series of short hill climb sets, then another short tempo run (e.g. 8 minutes). This form of tempo training is designed to allow an athlete to work on multiple aspects of training at once (I.e. lactate threshold, power and speed). Probably the form most used by sporting athletes as the season approaches.

Fartlek is a Swedish word meaning speed play. Fartlek training is a method that involves continuous training with interval training. This training technique is based around a lower intensity LSD training approach broken up with shorter high intensity efforts at regular intervals throughout a continuous session.

Fartlek training differs from traditional interval training approaches as it is largely unstructured with regular intensity and/or speed changes throughout the training session. While Fartlek training is usually employed by runners, the method can be applied to any form of cardiovascular training. It is a training method employed to take athletes above their lactate threshold for short periods of time (hard) and then allowing them to recover during lower intensity periods of work (easy). This allows an athlete’s system to practice dealing with rises in lactate and clearing it during the exercise session (Martin, 2023). Finney and Matos (n.d.) suggest that the “hards” should be completed at between 70-90% of HR max depending on training experience and that the “easys” should be completed at 50-60% of HR max,

This also makes Fartlek training great for field sport athletes as it mimics the ebb and flow of intensity during a game. Competition games are rarely start and stop these days, but more often higher intensity efforts followed by a need to recover while still moving.

Finney and Matos (n.d.) suggest that Fartlek training can be individualised for a range of training goals ranging from weight loss to top end speed, as well as developing high levels of general conditioning for a range of sports. This form of training is easily manipulated to suit a wide range of training outcomes with a trainer simply having to consider the work:recovery intervals associated with the sport of their athlete, the common high intensity effort and lower intensity recovery durations during a game.

Fartlek training session

There are many and varied forms of Fartlek training that we will look at shortly, but a standard running approach to Fartlek training might look like this:

Warm up	5-10 minutes of easy running
Main Workout	2 minutes at over 70%-90% of VO2 Max pace (higher end for elite, lower end for starters) followed by 2-3 minutes at easy pace (50-60% VO2 Max pace). Repeat 4-8 times, depending on level of training.
Cool down	5-10 minutes at easy jog.

The key benefits offered by Fartlek training include increased VO2 max, increased lactate threshold, improved running economy and fuel utilisation, and enhanced speed over distance. It is highly touted by many researchers and trainers as the best method to promote many of these physiological changes because it also offers outstanding flexibility in that variables can be adapted to suit a wide range of specific training outcomes (Finney and Matos, n.d.).

Applying the FITT principles to fartlek training

Type: While Fartlek training was developed for runners, the flexible nature of this training approach means it can be adapted to suit any type of cardio and it is now regularly used to develop speed and endurance across the cardio training spectrum. Finny and Matos (n.d.) suggest that Fartlek training is ideal for sports that consist of bouts of anaerobic sprinting mixed with aerobic recovery efforts such as football, rugby, volleyball, basketball etc). If your client is a sporting athlete, then the mode of training will be determined by the movement the use in their sport (e.g. running, swimming, rowing, canoeing, cycling etc). A general fitness client can of course choose a training mode they prefer (or even better, mix the training modes up to create a greater training stimulus for change).

Frequency: Fartlek training sessions should be considered as “speed work” sessions. Running Directions (n.d.) suggest that as a general rule of thumb most amateur runners should include a maximum of 2 speed-related sessions a week and that beginners should keep it to one session. This is because the “hards” in Fartlek sessions place considerable stress on the CV and muscular systems. Fartlek sessions should be followed up the next day by a lighter training session.

Time (Duration): The duration of a Fartlek session is fully dependent on the client and their training goals. For example, someone who’s goal is to compete over 5km would benefit from a Fartlek session where the main workout (Fartlek) portion is 15-20 minutes, whereas an experienced marathon runner would extend the Fartlek training portion of the workout to 60-75 minutes. In terms of sporting athletes, the duration of the workout will be dependent on the intensity of the session (which will reflect the phase of training). Typically, the use of Fartlek training in team sports is done using shorter more high intensity efforts than cardio athletes would use, so the Fartlek portion of the training sessions will last somewhere around 20 minutes and consist of more frequent high intensity efforts and shorter recovery periods than you would see in runners and cyclists (Anderson, n.d.). All Fartlek sessions should be preceded by a 5-10 minute warm up (at easy pace) and end with a 5-10 -minute cool down at easy pace.

For most team sport athletes wanting to place emphasis on the anaerobic system, the anaerobic (hard) portion of the workout would include efforts approaching near maximal speeds, followed by lower intensity recovery periods of less than 2 minutes, repeated for 4-5 bouts (or up to 8 bouts in very well-conditioned athletes). Once the Fartlek approach has been used for a few weeks, trainers will often add even more variability by adding short maximal sprints in amongst longer anaerobic hard runs and lower intensity recovery efforts to even better match the demands of sport (Finney and Matos, n.d.).

For athletes wanting to place emphasis on the aerobic system, the “hards” would be completed for up to 5 minutes at a moderate-high intensity pace followed by shorter “easys” over 1-2 minutes.

Intensity: The intensity of a Fartlek session will also depend on the training goal and level of condition of the client. In general, “hards” are performed at the higher end of the intensity range (80-90% effort) however, this is somewhat determined by how long each hard effort is. For example, a marathon runner will likely run longer “hards” than a basketball player. The shorter the “hard” the higher the intensity it should be completed at (and vice versa). The “easys” should be easy! These efforts should be thought of as active recovery, so they should be completed at a level of intensity that will allow the systems to recover allowing the next “hard” to be completed at the desired intensity. A common intensity for the “easys” is 50-60% of maximum effort.

Finney and Matos (n.d.) suggest that many trainers use a quite subjective approach to intensity allowing clients to use “feel” (or perception of effort) to complete their “hards and easys”. In other words, if the athlete feels like they are not yet sufficiently recovered to complete another intense repetition, they can choose to recover for slightly longer before attempting the next “hard”. The danger of using “feel” is that some less motivated athletes may not train at high enough intensities to elicit the desired training effects. Using heart rate monitoring approaches would be a far more effective means of delivering Fartlek sessions with these types of clients (Finney and Matos, n.d.).

Here are examples demonstrating how you can adjust the FITT principles in Fartlek training to achieve specific training goals and align with various sports. These Fartlek training approaches are suggested by Anderson (n.d.) and Finney and Matos (n.d.).

Applying progressive overload to fartlek training

Progressive overload is typically applied in Fartlek training by adjusting intensity or distance (rather than frequency). The variable that is manipulated will ultimately depend on the training goal of the client. Endurance athletes will likely apply progressive overload by increasing the distance of the training sessions, then by increasing the duration of the harder efforts (or by shortening the duration of the lower intensity efforts).

Team sport athletes will more likely apply progressive overload by moving from an initial aerobic focus with longer “easys” and shorter “hards”, to more frequent and intense “hards” and shorter “easys”. They will also add short maximal efforts into the workout to better reflect the needs of their sport.

Common approaches to Fartlek training

The great thing about Fartlek training is its versatility. This gives trainers the ability to manipulate the variables in a number of different ways to target specific training effects, or simply to add variety into CV sessions to keep client motivation levels up. While the approaches detailed above are fairly standard approaches to Fartlek training, there have been far more adventurous approaches created for this form of training that can add some real variety to training sessions and motivate clients to give their best. Here are some common approaches from Olympic marathon runner Matea Matosevic (n.d.):

Fartlek by feeling

A very unstructured form of Fartlek training that is essentially created by “feel”. After a 5-10 warm up the athlete simply alternates between faster and slower movement speeds. They are encouraged to run at faster speeds until they feel tired then slow down. Once they feel they have recovered sufficiently, they should speed up again. These sessions are usually completed over a set period of time, or a nominal distance.

Suitable for general fitness clients, or endurance athletes who are highly motivated and can be trusted to work hard. Can be improved by monitoring heart rates throughout (but this somewhat defeats the purpose of the method).

Landmark Fartlek

Similar to the Fartlek by feeling approach, but this time the workout intensity is determined by landmarks along the route of the session. For example, an athlete may complete the warm-up and then look in the distance at a given landmark. They will then run hard until they reach the landmark, then ease off and recover before picking another landmark to push to. Landmarks could include using trees, buildings, streetlights etc. This works for almost any cardio mode from cross-country skiing to rowing.

Suitable for a range of clients. Best for those athletes who are highly self-motivated to work.

Music Fartlek

Music Fartlek allows the music to dictate the speeds. It can be used in one of two ways. The first involves picking a selection of slower and faster-beat songs for a playlist. The ratio of these should be selected depending on the energy system targeted, for example, if targeting the aerobic system, you would have more slower tempo than faster tempo songs. If targeting the anaerobic system, you would select more shorter duration faster tempo songs and fewer longer duration slower songs. The 2nd approach is more suitable for repeated sprint training efforts and involves running hard during the chorus of a song and running the other parts of the song at slower speeds.

An example of this type of session is as follows:

1. Warm up: 2 songs (slower beat)
2. Main workout: 6 upbeat songs: run the chorus hard and the other parts easy
3. Cool down: 2 songs (slower beat)

Suitable for general fitness clients. Could also be useful for athletes if well structured.

Buddy Fartlek

Involves running with a buddy where one of you determines the pace of a “hard” and the other chooses the distance (could utilise landmarks for this). Be careful with this approach! It is vital that you and your buddy are at a similar level of conditioning for this to work.

Suitable for those who prefer exercising with others and those who like a little competition.

Short Fartlek: Time-based and distance-based

Short fartlek (time-based) is a type of structured fartlek training that includes 1 to 3 minutes of fast running with 30 seconds to 2 minutes of active recovery (easy jogging).

A 40-minute example:

1. Warm-up: 10 minutes of easy jogging
2. Main Training: 20 minutes of running (1 minute hard/1 minute slower) x 10
3. Cool down: 10 minutes of easy jogging

Short fartlek (distance-based) is a type of structured fartlek training that includes 100m to 500m of faster running with 50m to 400m of active recovery. This type of training is preferable to do on a running track as the intervals are short and it is easier to follow the training without looking at the watch.

An 8km example of this method:

1. Warm-up: 2 km of easy jogging
2. Main part of training: 4 km of running (200m of faster running / 200m of slower running) x 10
3. Cool down: 2 km of easy jogging

More suited to athletes and sports competing over shorter distances, or to those that typically do their training in a gym environment.

Long Fartlek (time-based and distance-based)

Long Fartlek (time-based) is a type of structured fartlek training that includes a minimum of 3 minutes of faster running. Active recovery should last at least half the time of the fast run. For example, if you run fast for 4 minutes, active recovery should last at least 2 minutes.

Example of a 45-minute session:

1. Warm-up: 10 minutes of easy jogging
2. Main part of training: 30 minutes of running (4 mins of faster running / 2 mins of slower running) x 5
3. Cool down: 5 minutes of easy jogging

Long Fartlek (distance-based) is a type of structured Fartlek training that includes a minimum of 500m of faster running. Active recovery should last at least half the distance during a fast run. For example, if you run fast for 1 km, active recovery should last at least 500m.

Example of an 11km session:

1. Warm-up: 2 km of easy jogging
2. Main part of training: 7.5 km of running (1 km of faster running / 500m of slower running) x 5
3. Cool down: 1.5 km of easy jogging

Suitable for endurance athletes and those trying to improve their VO2 max and increase lactate threshold.

Ladder Fartlek (both time-based and distance-based)

Ladder Fartlek (time-based) is a type of structured Fartlek training in which the main part of the training has fixed time intervals that become progressively higher or lower.

Example of a 49-minute session:

1. Warm-up: 10 minutes of easy jogging
2. Main part of training: (29 minutes of running)
   • 8 minutes of faster running / 4 minutes of slower running
   • 6 minutes of faster running / 3 minutes of slower running
   • 4 minutes of faster running / 2 minutes of slower running
   • 2 minutes of faster running
3. Cool down: 10 minutes of easy jogging

Ladder Fartlek (distance-based) is a type of structured Fartlek training in which the main part of the training has fixed distances that become progressively higher or lower.

Example of an 8km session:

1. Warm-up: 2 km of easy jogging
2. Main part of training: (4.2 km of running)
   • 1 km of faster running / 500m of slower running
   • 800m of faster running / 400m of slower running
   • 600m of faster running / 300m of slower running
   • 400m of faster running / 200m of slower running
   • 200m of faster running
3. Cool down: 1.8 km of easy jogging

Suitable for those who’s sports require hard running efforts of variable lengths.

Pyramid Fartlek (both time-based and distance-based)

Pyramid Fartlek (time-based) is a type of structured Fartlek training in which the main part of the training has fixed time intervals that become progressively higher/lower and then vice versa.

Example of a 46-minute session:

1. Warm-up: 10 minutes of easy jogging
2. Main part of training: (26 minutes of running)
   • 2 minutes of faster running / 1 minutes of slower running
   • 4 minutes of faster running / 2 minutes of slower running
   • 6 minutes of faster running / 3 minutes of slower running
   • 4 minutes of faster running / 2 minutes of slower running
   • 2 minutes of faster running
3. Cool down: 10 minutes of easy jogging

Pyramid Fartlek (distance-based) is a type of structured Fartlek training in which the main part of the training has fixed distances that become progressively higher/lower and then vice versa.

Example of a 9km session:

1. Warm-up: 2 km of easy jogging
2. Main part of training: 5 km of running
   • 400m of faster running / 200m of slower running
   • 800m of faster running / 400m of slower running
   • 1200m of faster running / 600m of slower running
   • 800m of faster running / 400m of slower running
   • 400m of faster running
3. Cool down: 2 km of easy jogging

Suitable for those who’s sports require hard running efforts of variable lengths.

Golf course Fartlek training

A really inventive approach to Fartlek training. The rules are as follows:

• Par threes (shortest holes: 150-200 metres): 90-100% sprint.
• Par fours (middle distance holes: 350-450 metres. These make up the majority of holes on the course): 70% maximum effort run (moderate).
• Par fives (longer distance holes: 450-600m): 50% of maximum pace (easy).
• Walk/jog one lap of the green and then move to the next tee box and continue.

Completing 9 holes on most courses will cover around 3km and 18 holes around 6km. If doing 18 holes, it is suggested you take a 2-3-minute rest after 9 holes (a great chance for a water break).

Suitable for those who love the outdoors and like some variety in terrains.

Keeping Fartlek training relevant to team sport

While Fartlek training was designed for runners, it is a great conditioning tool for team sport athletes also. However, it is important that the running distances and intensities of different efforts relate to the demands of the sport of the athletes in question. In order to do this, a trainer needs to have an excellent working knowledge of the demands of the sport that their client plays including average running distances and speeds during gameplay. For most major sporting codes this information is readily available due to increasing use of GPS tracking systems in elite sport.

Practical application example: Rugby 7s

A little research can uncover the average running distances and speeds of elite rugby sevens players. The following data comes from 2 studies performed by Ball, Halaki and Orr (2019) and Willemse (2012). This data shows the locomotion demands of men (club) and women (international) players and is summarised as follows:

• Average distance covered per game: 1580m (males), 1156 (females)
• Walking: 549m (men), 462m (females)
• Running at less than 14km/hr: 570m (males), 300m (females)
• Running at 14-18km/hr: 245m (men), 255m (females)
• Running at 18-20km/hr: 80m (men), 57m (females)
• Full sprints (20km/hr +): 138m (men), 84m (females)
• Longest sprints: 67m (males), 54m (females)
• Percentage of time spent at over 80% maximum heart rate: 75% (both men and women)
• Work:rest ratio: For every minute working they spend 30 seconds in active rest

So, what would be an ideal Fartlek training method for 7s players?

7s players run the most distance at less than 14km/hr. 7s players run hard the most distance at between 14-18k/hr and at over 20km/hr. The initial Fartlek approach to use with 7s players would be to design a starting session of around 3km. This is considerably longer than what they run in a game, but the running speeds would be set at lower than the game-day running. To start with the “easys” should be set at less than 14km/hr and the “hards” set at between 16 and 18km/hr. A good approach would be to use a short time-based Fartlek approach of 1 minute easy, 1 minute hard. As the competitive season approaches, it would then be prudent to adapt the variables to match game-day requirements. This would see the “easys” run at 14km/hr and the “hards” fluctuating between 18km/hr and 20+km/hr. The best approach would also be to try and replicate game distances run at these speeds, so this would mean hard runs of around 50-70m with around 30-60 second easy efforts. The total distance of the Fartlek workout would start to resemble the game day movement distances (e.g. 1200-1500m).

Trainability of lactate threshold

Lactate threshold is thought to be the most trainable endurance performance quality for endurance athletes.

The following image shows how trainable lactate production or lactate threshold is. This graph shows a swimmer who trained for 7-months and the lactate in blood after a 200m swim. As you can see, blood lactate accumulation has fallen steadily across the training months to a point where the athlete can swim at a speed at the end of the training block that produces low levels of lactate whereas the same pace elicited extremely high levels of blood lactate in the first month of training.

According to Lactate Threshold Training: The Definitive Guide (n.d.) untrained individuals can increase their lactate threshold from a training intensity of around 55-60% of VO2 Max to efforts over 90% of VO2 Max. To put this in perspective, this effectively means an athlete could conceivably stay aerobic at exercise intensities of 80-90% of max effort!

If you are thinking that maintaining aerobic exercise at 80-90% of your maximum effort sounds a little far-fetched, let’s take a quick look at some data from Eliud Kipchoge’s unofficial sub two-hour marathon effort in 2019. We will take a closer look at this remarkable effort shortly, but first, let’s see what sort of pace and therefore lactate threshold he was able to maintain for the 2-hour race.

According to Burgess (2019) Kipchoge ran every kilometre of the 42.2km run at splits between 2.48-2.52 minutes/km. This means he ran an average pace of 21.2km/hr (next time you are in the gym, try out this pace on a treadmill and see how long you last!).

Further to this, Dalzell (2022) suggests Kipchoge maintained an average heart rate of 177 bpm and got as high as 188 during his official world record marathon effort of 2 hours. At the time of the world record, Kipchoge was 35 years old. This means his estimated maximum heart rate was 185. An average heart rate of 177 means he was operating at well over 90% of his maximum HR......for 2 hours!

According to Sayer (2023) this ability to maintain high heart rates is pretty typical for elite marathon runners. Sayer (2023) reviewed 11 studies and concluded that elite marathon runners operate at somewhere between 80 and 90% of their heart rate max.

Lactate threshold training

Lactate threshold training involves training at intensities that are just below your lactate threshold. This places stress on the CV system (at the lower end of the stress continuum) which leads to general adaptation.

The following video explains the concept of “threshold training”.

Lactate threshold testing

Just like 1RM testing, distance over time tests and VO2 Max testing, lactate threshold testing is a useful tool that allows you to develop a strategic training plan without guesswork. Knowing your lactate threshold allows you to programme training intensities with accuracy, giving you the certainty that your training will lead to optimal improvements. Testing lactate threshold periodically also allows you to check the effectiveness of each training block.

Lactate threshold testing is typically done in a lab setting by drawing blood at intervals during an incremental exercise test. The test is performed using a process that is very similar to VO2 Max test protocol. The test is typically performed on a treadmill or stationary cycle (it can be performed for other cardio modes also but blood collection is often difficult (I.e. with rowing or swimming) meaning athletes would have to pause the exercise to collect the sample (potentially affecting results). During the test the exercise intensity starts at a comfortable pace and then is increased approximately every three minutes with blood samples taken at the end of each period.

The exact protocols for a lactate threshold test from The National Strength and Conditioning Association (NSCA, 2020) include the following.

• The purpose.
• The equipment.
• The warm-up.
• Selecting a starting work rate.

Let’s read about each in more detail.

The purpose

This incremental test is designed to establish a baseline for lactate in the blood at comfortable exercise intensities, then isolate the point at which significant blood lactate begins to accumulate in muscle and spill into the bloodstream. The results of a lactate threshold test can be seen in the image below. In the graph, you can see that a baseline blood lactate level of around 1mmol of lactate per litre of blood is established in the early workout stages and that a work rate of around 250 Watts there is a noticeable increase in blood lactate in this subject. This indicates their OBLA (Onset of Blood Lactate Accumulation). The lactate threshold is the last working intensity/pace before OBLA occurs.

The equipment

In order to perform a lactate threshold test you need the following:

• Disposable gloves - These are for the protection of the person collecting the blood sample.
• A lancet for drawing blood – These puncture the skin (usually of a fingertip or earlobe) to cause a drop of blood to form on the skin.
• Disposable strips for collecting blood droplets – these are then inserted into the lactate analyser
• A blood lactate analyser – a small machine that detects lactate in the blood sample and produces a reading.

The warm-up

Prior to the start of a lactate threshold test, the subject should perform an adequate warm-up of approximately 10 to 15 minutes beginning at a low work rate and progressing to an intensity that is similar to the starting work rate for the lactate threshold test. The warm-up serves two purposes:

• The oxidative energy pathways need several minutes to reach optimal operating capacity. Early in exercise, the body relies heavily on glycolysis to meet ATP demand, resulting in high levels of lactate production. This increased rate of lactate production could lead to blood lactate levels in the initial stages of the test that may not accurately reflect the blood lactate production and consumption dynamics when mitochondria are functioning at their optimal levels.
• People who have never had a lactate threshold test may be apprehensive or nervous before the test begins. These feelings may result in a rise in circulating levels of epinephrine, which can cause increased rates of glycolysis and lactate production. By performing a warm-up prior to the start of the lactate threshold test, subjects can reduce anxiousness and their rates of lactate production, leading to more accurate lactate levels during the early portion of the test. Interestingly, resting (anxious) subjects can display lactate levels in blood similar to athletes undertaking intense exercise (NSCA, 2020)

Selecting a starting work rate

Starting work rates and the progression of work rates over the course of the test are dictated by the condition level of the client. This is because the lactate threshold of individuals varies considerably between untrained and trained. The Exercise Physiology Laboratory of the University of Virgnia suggests the following average lactate threshold figures for different levels of training:

• The average person reaches their lactate threshold at ~50-60 percent of their VO2 max
• Recreational athletes reach their lactate threshold at 65-80 percent of their VO2 max
• Elite endurance athletes reach their lactate threshold at 85-95 percent of their VO2 max

You can see the difference in blood lactate accumulation between trained and untrained subjects in the graph below (related to their VO2 Max). Trained subjects are able to work at a higher percentage of VO2 Max before significant lactate accumulation (OBLA) occurs.

Ideally, a test concludes within 12-20 minutes. A test that starts at too high an intensity may not allow the subject to establish a baseline lactate reading, making identification of a threshold almost impossible. It is generally best to be conservative when selecting starting work rates, however, a conversation with the client about their usual running speeds should help you determine an appropriate starting point. The test will generally end one increment after a noticeable spike in blood lactate has been observed.

The following video shows the process and explains the purpose of a lactate threshold test.

Estimating lactate threshold

What if I don’t have lactate threshold testing equipment? Don’t worry, there are a few different ways of estimating a client’s lactate threshold without the need for fancy equipment. There are also plenty of training indicators that can be monitored during a client’s workout that indicate lactate threshold has been reached.

When you exercise at any intensity above “easy”, your body goes exhibits a couple of ventilatory thresholds that can be used to indicate lactate threshold. These thresholds are essentially when you notice your breathing noticeably change. According to Parker (2022) the first of these ventilatory thresholds (V1) occurs when exercise intensity increases to a point where you can no longer hold a conversation comfortably, but you can still respond with short replies. V1 is typically the intensity where lactate threshold training should be completed. The second ventilatory threshold (V2) occurs when lactate begins to accumulate faster in your muscles than it can be removed. This typically occurs at the same time as OBLA. At this intensity, your breathing becomes rapid and heavy (puffing), and you can no longer speak during exercise. This intensity is too high for generic lactate threshold sessions as it cannot be maintained for long enough to cause enough of a training effect, however, it is worthwhile knowing at what intensity V2 occurs at for training sessions where you want to train above and below lactate threshold. Using the ventilatory thresholds is an easy (and non-invasive) way to estimate lactate threshold training zones.

You can also estimate lactate threshold running pace using an online running pace calculator. While these are generic calculators that don’t take into account age, gender or running experience, they can be a useful means of giving a starting point for working out target running speeds (that can be adjusted later). All you need to have to use one of these calculators is a goal distance and completion time. See the following example of one of these free online running distance calculators. You can access this from Vdoto2.

Tests for estimating lactate threshold

Lactate threshold is essentially the maximum pace you can maintain for 60 minutes. Unfortunately, sustaining this pace for an hour is essentially what you would try to do in a race, so is a pretty tough ask for most people to do as a baseline test. Luckily, there are a number of shorter running tests that can used to help estimate lactate threshold. Note, that a meaningful workout should be conducted prior to the start of any of these tests. This warm-up should last 10 minutes and gradually increase pace until you settle on what you believe is a pace you maintain for the duration of the test.

20-minute Test (Boyd, n.d.)

It appears that the maximum pace you can sustain over 20 minutes is a pace approximately 5% higher than the pace a recreational runner could maintain for 60 minutes. Therefore, a simple calculation following your best 20-minute running effort can be used to estimate your lactate threshold training pace.

To conduct this test, you will need a GPS fitness tracking device (watch or phone app) that can trace your running pace and heart rate (note: it is also suggested that if a chest strap is available for tracking heart rate this should be used instead of relying on wrist-worn heart rate trackers which may not be accurate enough). Perform this test when you’re not fatigued by heavy exercise the day before. Use a level track, level road, or a treadmill set at 1% incline. You will also need a heart rate monitor.

The test itself is simple. Run at a constant pace you can maintain for 20 minutes. This should be a V1 pace (not V2). Make sure you don’t start out too fast and taper off as you get tired. Similarly, you don’t want to start out too easy and have to ramp things up in the 2nd half of the run. Once you are finished, note your average heart rate throughout the 20-minute run. You should also note your average running pace throughout the 20 minutes.

Equations for working out lactate threshold running pace and heart rate zones

The difference between your lactate threshold pace and 20-minute pace is 5%. Therefore:

Lactate Threshold Running speed is 5% slower than your average speed over 20 minutes. If my average 20-minute running pace was 4 minutes 50 per kilometre. Then the equation to work out my lactate threshold running pace would be:

We can also work out our target lactate training threshold heart rate zone from this information. For example, if my average heart rate over the 20-minute test was 170 bpm. Then my target heart rate training zone for lactate threshold would be 5% lower than this. Therefore:

30-minute time trial

Start by doing some light cardio activity for 10 minutes, like walking or an easy jog, to warm up your body and prepare it for exercise. Gradually Increase the intensity of your warm-up towards the end of the 10 minutes. Try to settle on a pace (and HR) that you think you can maintain for 30 minutes.

Next, start running at the fastest speed you can maintain for 30 minutes. This needs to be a steady pace over the course of the 30 minutes. Procedure: Note your heart rate after 10 minutes and continue running. Note your heart rate at the 30-minute mark also. Add your 10-minute heart rate to your 30-minute heart rate and divide by two to find an average heart rate. For example, if your 10-minute heart rate was 155bpm and your 30-minute heart rate was 170bpm then the equation would be:

Parker (2022) suggests the Tempo and Lactate threshold heart rate training zone is between 71-85% of HR Max. She believes that knowing this makes it possible to estimate your lactate threshold heart rate training zone using the Karnoven formula. She suggests using the following approach:

1. 220 – age = Max HR
2. Max HR – Rest HR = Heart Rate Reserve 
3. HRR x 0.71 + Rest HR = Bottom end of lactate threshold training zone
4. HRR x 0.85 + Rest HR = Top end of lactate threshold training zone

The suggestion is that those who are more conditioned will need to work towards the end of this range, while those just starting out will be best to work at the lower end of this range.

Example:

A 25-year-old with a resting heart rate of 70bpm wants to work out their lactate threshold target HR zone. They would use the following equation:

220-25 = 195bpm

195 –70 = 125bpm (HRR)

125 x 0.71 = 88.75 + 70 = 159bpm

125 x 0.85 = 106.25 + 70 = 176bpm

Lactate threshold should occur somewhere between 159-176bpm

Sex differences

There has been conflicting evidence around the difference in lactate threshold and maximum lactate tolerance between men and women. However, studies performed more recently and with larger subject groups appear to suggest that there is little to no difference between men and women when it comes to lactate threshold.

Rascon et al (2020) examined the difference between males and females in determining exercise intensity and found that despite females exhibiting a lower VO2 max and having higher heart rates at the same power outputs (at different intensities), there was not a significant difference in blood lactate levels between men and women during exercise at a range of intensities. This finding is supported by Wheatley et al (2014) and Demello et al (1987) who showed that there were no differences in blood lactate levels between males and females at 5 different exercise intensities from very low to high intensity. This is further supported by a range of other studies using different training modes and intensity levels. Blood lactate levels have also been shown to be dependable across multiple studies finding that males and females achieve maximal lactate steady state at similar relative intensities (Rascon et al, 2020). The few studies that have reported a difference between male and female blood lactate differences (particularly during lower-intensity exercise). These studies included smaller sample sizes and had issues in study design that presented issues with their validity (Rascon et al (2020).

It would appear that, based on the available literature, trainers should have confidence in identifying lactate threshold and prescribing sessions using the techniques discussed , as the lactate production and clearance rates of males and females appear to be very similar.

The following video summarises the key points relevant to the use of sodium bicarbonate as an ergogenic aid.

Right, time to apply what you have learned. Head to your assessment for an assessment guide video and instructions on submitting your assessments.

The assessment guide video explains your assessment task, which requires you to use the information you have learned on this topic to help a case study client.

This assessment will require you to apply the knowledge you have learned and practised by completing the following tasks:

• Design a Lactate Threshold Training mode programme for an Athlete
• Justify your selection of programme variables (e.g. modality of training, exercise selection, sets, reps, rest etc.)
• Design a progressed programme for the end of the mesocycle
• Justify the changes you implement to the progressed programme
• Select a relevant fitness test to test this fitness component.